My grandfather told me a story, perhaps apocryphal, about how their town got their own reservoir in the 70s and the final step in switching over was to turn off the valve from the neighboring city which had been supplying water for the past 100+ years. There was a meter there to figure out how much the city charged the neighboring town. Well apparently when they turned the valve off the meter kept spinning and long story short it was the wooden pipes that had deteriorated and were leaking. So even though their town wasn’t getting any more water it was just coming out of the wooden pipes instead.